Aerogels are known to provide good thermal insulation properties and have attractive thermal protection per unit weight as compared to other materials. Materials with high thermal insulation such as aerogels are required for ever-increasing speed utilized in vehicles, particularly aircraft. This is particularly the case where vehicles experience severe heat loads for extended periods of time. Unfortunately, aerogels are difficult to apply to surfaces that require protection. Aerogels are available in solid or, more usually, flexible blanket forms and are not conventionally sprayed. Neither the solid or blanket form is as readily applied to a surface as a sprayed material. Aerogels can be applied by a spray application process wherein aerogel-binder compositions are used for application of the aerogel, where the binder holds the aerogel particles together and to the surface to which it is applied. However, the binder material has less attractive thermal performance as compared to the aerogel; consequently, substitution of a portion of the aerogel for the binder presents a disadvantage. Accordingly, there is a need for improvement to thermal protection systems which are based on aerogel insulating materials.